Solution:
Strabismus (squint) is when both eyes are not co-ordinated in focussing on the same point. Squints in adults and children have different effects. In an adult it tends to cause diplopia (double vision). In the young child (less than about eight years old) it can cause amblyopia. It may also indicate that visual acuity has been affected by cataract or refractive error, or that the child has some other serious condition such as retinoblastoma, cranial tumour, or myasthenia gravis.
As children may not complain of visual symptoms, the examiner should question the parents, including asking questions about any family history of refractive errors and squints. He should also enquire about birth trauma or neurological damage.
The examiner should check visual acuity first. If it does not improve with spectacles or a pinhole intraocular problems or amblyopia should be considered. Eye movement indicates whether there is a paralytic squint (one which occurs in only certain directions due to paralysis of the extraocular muscles which normally pull the eye in that direction); an adult will complain of diplopia with an increasing degree of separation of images in the direction of paralysis. A simple inspection of the eyes should indicate large squints, although the examiner should beware of being misled by pseudosquints. Corneal reflections should be symmetrical; if not, they indicate the degree of squint present. The cover test examines for a manifest squint (one which is always present) and the alternate cover test examines for a latent squint. In the cover test, the examiner covers one eye and the examiner watches the contralateral eye to see which direction it moves, and vice versa. In the alternate cover test, the examiner covers and uncovers one eye, looking for movement in that eye when he uncovers it. He repeats this for the other eye. Tests for squints should be performed both for close and distance vision.
Treatment for squints must include correcting visual refractive errors first. Then, orthoptic devices and exercises are considered, and, finally, surgery is considered. In children, there is a risk of amblyopia if the condition is not treated before the age of eight years.
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